Do you mean this year? Wow, that is soon.
The room rates are the lowest until Feb 15th. Any stay that begins on the 15th or sooner will get the lower 'value season' rate for the entire stay.
That said, there may be a discount code in the early spring. No one knows for sure, but they do sometimes put out a code for May. See the resort board for more info on that.
You will need two rooms if you stay onsite in a WDW resort (I just realized I was assuming you would, some people don't- I always do) or possibly a cabin at WL would work. Value season rooms at value resorts are $79 a night plus tax so really not too bad.
You have a lot to decide. Tickets, where to stay, and does the dining plan make sense for your family if you stay onsite. A good place to find info (besides here) is
www.allearsnet.com and
www.mousesavers.com
I also like the pay to view ($25 or so) site
www.tourguidemike.com
The best book, I think, is The Unofficial Guide to WDW. Make sure to get the newest edition as there have been a lot of changes. I think 2006 is out or will be soon.
As far as crowds go, anytime school is in and there are no holidays is a good bet, so Feb and early May would be my picks. Avoid Spring Break at all costs.